The present invention relates to an ultrasonic shower cleaning apparatus for ultrasonically cleaning articles with a shower of cleaning liquid and associated ultrasonic waves.
It is well known that an ultrasonic shower cleaning apparatus uses a shower of cleaning liquid to ultrasonically clean a liquid crystal display, a semiconductor wafer or other articles. One such apparatus is shown in FIGS. 7 and 8. As shown, a conventional ultrasonic shower cleaning apparatus 20 includes a cylindrical casing 21, and a nozzle 22 mounted to the downstream end of the casing 21. An ultrasonic vibratory element or ultrasonic transducer 23 of a circular disk is oriented to face the upstream end of the nozzle 22. An inlet port 24 is formed in the lateral periphery of the casing 21 to receive a cleaning liquid. The cleaning liquid fed through the inlet port 24 is discharged or spouted from the downstream end of the nozzle 22.
The nozzle 22 has an outlet port 22a. The outlet port 22a has a hollow circular upper section 22a.sub.1, of a fixed diameter, and a conical lower section 22a.sub.2 tapered from the upper section 22a.sub.1 toward its downstream end. One objective of this design is to provide a strong stream of the cleaning liquid as spouted through the downstream end of the nozzle 22. Another objective is to focus ultrasonic waves to a given focal point by allowing some of the ultrasonic waves emitted by the ultrasonic transducer 23 to pass straight through or along the axis of the outlet port 22a and causing the other ultrasonic waves to be reflected within the lower section 22a.sub.2 before they exit from the downstream end of the nozzle 22. This increases the intensity of ultrasonic energy and enables more effective cleaning of articles placed on such a focal point.
Reference numeral 25 denotes three bolt holes (two of them are shown in FIG. 7) formed in the lateral periphery of the casing 21 to secure the ultrasonic shower cleaning apparatus 20 in place. Referring specifically to FIG. 8, the ultrasonic shower cleaning apparatus 20 is secured to a suitable support by bolts 26. A feed pipe 27 is coupled to the inlet port 24 to feed a cleaning liquid thereto. An adapter 28 is attached to the upper end of the casing 21 to feed electric power to the ultrasonic transducer 23. The adapter 28 has a cord 28a connected to an ultrasonic generator (not shown).
In the apparatus 20 of FIG. 7, ultrasonic waves are focused to a point downstream of the nozzle after they propagate from the ultrasonic transducer. This arrangement enables effective cleaning of an article when placed on that point, but requires fine adjustment of the distance between the article and the tip of the nozzle. This adjustment is cumbersome, and satisfactory cleaning can not be effected on a constant basis unless such fine adjustment is made.
Accordingly, it is an object of the present invention to provide an ultrasonic shower cleaning apparatus which eliminates the need to finely adjust the distance between a tip of a nozzle and articles to be cleaned and which facilitates positioning of articles relative to the tip of the nozzle.